See Du Cange, who produces this as an instance, "Quod Ministellorum munus interdum praestabant milites probatissimi.
Interdum lacrymæ pondera vocis habent=--Sometimes tears have the weight of words.
Interdum vulgus rectum videt, est ubi peccat=--Sometimes 45 the common people judge aright; at other times they err.
Pecuniam in loco negligere / Interdum maximum est lucrum=--To despise money on proper occasions is sometimes a very great gain.
Etiam oblivisci quod scis, interdum expedit=--It is sometimes expedient to forget what you know.
The interdum facta denotes actions repeated at considerable intervals of time; the nonnunquam facta, actions repeated at shorter intervals; the aliquando facta, actions repeated at very distant intervals of time.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "interdum" in a variety of sentences. We hope that you will now be able to make sentences using this word.